<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<script>
var s = "abc你好";
var c = s.charAt(3)
console.log(c);
console.log(s[5]);
console.log(s.charCodeAt(0));   // 获取到字符的 Unicode 的码
console.log(s.charCodeAt(4));

// 根据一个编码, 得到编码对应的字符
var c1 = String.fromCharCode(33333)
console.log(c1);

var arr = [];
for(var i = 0; i < 10; i++){
    arr.push(i);
}
for(var i = 0; i < 26; i++){
    arr.push(String.fromCharCode(97 + i));
    arr.push(String.fromCharCode(97 + i).toUpperCase())
}
console.log(arr);

</script>
</body>
</html>